I meant N54 had more potential, but I guess you know what I meant. I have not dug into into the dynos really, and I believe you need a serious of testing of multiple cars to be able to make that judgement, but lets say you are right. My judgement is not purely based on the HP/TQ output of the engine. I believe the stock engine is overall a better engine on N55 due to enhancements they made. I.e, fuel efficiency and reduced lag. I have also seen that f30 N55 is underrated by factory and actually puts out ~315 hp...

There have been multiple dyno testings of each car, the N54 just makes more horsepower than the N55, period. There are no ifs ands or butts about it. N54 is more underrated if you would from the factory than the N55.

That said, not having to deal with high pressure fuel pump issues and the aforementioned gas mileage gains are a plus from a convenience perspective. Just wish the car pulled harder up top, at least as much so as the N54, which I even felt fell flat on its face up top.